The present invention relates to apparatuses for displaying spectrums of multichannel signals, and more particularly to a spectrum display apparatus which displays the level of channel signal of higher level for every plural number of bands of respective multichannel signals.
In the prior art, a spectrum displaying apparatus having a plurality of band-pass filters for dividing an input audio signal into a plurality of frequency bands and a display device for displaying in bar-graph form the levels of the signals of each band divided by the band-pass filters has been reduced to practice. At the time of recording of an input audio signal, for example, by watching the display device, the bands in which the levels are excessively high are determined, and by operating level adjusters provided to correspond to the above mentioned bands and adapted to adjust the respective levels of the bands, all bands are so adjusted that they assume appropriate sound recording levels. As a result, good sound recording can be accomplished without distortion over all bands.
As a spectrum displaying apparatus for signals of a plurality of channels (hereinafter referred to as multichannels), the provision of a plurality of spectrum displaying apparatuses in correspondence with the multichannel signals is conceivable as a possibility. However, the provision of a plurality of spectrum displaying apparatuses in this manner entails high cost and, furthermore, requires displaying device or parts installation space of great area in a front panel of an audio signal recording and/or reproducing apparatus. Furthermore, simultaneous surveillance of a plurality of spectrum displaying device is difficult in actual practice.
Accordingly, there has been a device wherein, for example, one spectrum displaying device is provided for every two channel stereo signals, and either one of the two channel signals is selectively supplied to the spectrum displaying device by manually switching a changeover switch, the spectrum displaying of that selected signal thereby being carried out. However, this device has a disadvantage in that the state of the level at any one time of the signal of the other channel which is not being selected by the switch is completely unknown.